Of a total of 83 preadolescent victims of felonious homicide in the city of Detroit from the year 1940 to 1965, 35 were slain by their mothers. In the vast majority of instances, these mothers were judged to be overtly psychotic at the time of the act. Most frequently they were suffering from a psychotic depression. A considerable number appear to have been schizophrenic. Early recognition of the hallmarks of these illnesses is essential in the prevention of maternal filicide.